What is the 250k hours stat from? Its certainly not total hours from a fleet leader. In fact the gearbox that failed in October and May were very low hours.
Whoever stated that, presumably was taking a guess at the combined total hours of EC225 flying in the last approx 7years.
In May the engineering analysis of G-REDW show that the broken components triggered the chip detectors in the sump I believe - which means bits of metal frag was in the oil.. That isn't good but for the fact the pumps aren't working so it goes nowhere unless of course you can suggest fragments travelled before the pumps fail totally (after all they got to the chip detectors).
It might be possible that in the May ditching, the broken shaft could have fallen against the single chip detector in the sump and damaged it. As regards "bits of metal frag", when a weld breaks there arent any to speak of; perhaps minute particles which couldn't significantly damage other components.
Beyond that in the case of G-CHCN the HUMS data shows that the Red alarm threshold had been exceeded. So regardless of one pilot suggesting the vibration is insignificant it's significant enough to produce a red alarm.
The increased vibration thresholds to produce an amber or a red alarm are also minute, in order to give early warning of failure.
The 30 min emergency lube is of course a safety net - but not in all circumstances. Given EC225 MGB issues since 2009 you would be almost crazy to continue flying for 30 mins knowing you had a MGB issue when you could have quickly ditched in flat sea alongside a ship. When bits of gearbox fire themselves out of the casing or you loose the main rotor parts being lubricated is irrelevant.
Agreed completely. Calm sea and ship in sight which I've spoken to, or land half an hour away? It's a no-brainer.
It is also wrong to say it's flown for millions of hours on the same design until 18 months ago. Were that the case you would find the fix to be simple.
That's not exactly what was meant. There's no suggestion been made that the shaft design was changed 18 or more months ago.
The current lines of investigation by EC include any possible changes affecting the whole gearbox, which could affect the shaft adversely. One thought is that mods to the engine management system in the last 18 months or so, could have changed torque and vibration characteristics detrimentally for the pump drive bevel shaft.